minimization of vibrations for machining of explosive …

e-ISSN: 2582-5208 International Research Journal of Modernization in Engineering Technology and Science

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Volume:03/Issue:09/September-2021 Impact Factor- 6.752 www.irjmets.com

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MINIMIZATION OF VIBRATIONS FOR MACHINING OF EXPLOSIVE MATERIAL

Shantanu Pawar*1

*1UG Student, Savitribai Phule Pune University, Pune, Maharashtra, India.

ABSTRACT

Propellant is a chemical mixture that is burned in a rocket to produce thrust and is made up of fuel and oxidant.

Fuel is a substance that burns when combined with oxygen-producing gas for propulsion. Composite solid

propellants based on hydroxyl-terminated polybutadiene (HTPB) have emerged as the workhorse propellants in

modern solid rocket motors. HTPB being an explosive material machining conditions may affect process

performance in altogether different manner than in a case of conventional machining. In present work, the

machining of HTPB is done by the special purpose CNC vertical milling machine. For machining of propellant hollow

contouring cutter is used with non-sparking conical inserts. The scope of our project is to design a new milling cutter to

improve surface finish of the HTPB based propellant and eliminate major causes of vibration while carrying out

machining technique. Also optimizing the machining parameters by performing different optimization methods

is one of the priorities

Keywords: Propellant, HTPB, Explosive.

I. INTRODUCTION

Explosive material is a kind of reactive substance that contains a lot of potential energy, if it is released

suddenly, it will explode, usually accompanied by the generation of light, heat, sound and pressure. Explosive

materials can be classified according to how fast they expand.

Now, propellants and explosives are classified as combustible materials, and their ingredients contain oxidizers

and fuels. During the combustion process, propellants and explosives will release a large amount of gas at high

temperatures, and spontaneously ignite in the absence of oxygen in the surrounding atmosphere.

propellant is a chemical mixture that burns to produce rocket thrust, and is composed of fuel and oxidizer. Fuel

is a substance that burns when combined with a gas that produces oxygen for propulsion. The oxidizer is a

reagent that releases oxygen when combined with fuel. Propellants are classified according to their liquid, solid

or mixed state. Solid propellants are divided into dual-base propellants, compound propellants, high-energy

compound propellants (HEC), double-base modified compound propellants, and minimal characteristics

propellants (smokeless). Among these types of propellants, compound propellants are mainly used for other

propellants due to their high performance and moderate cost. Today, the minimal signature propellant

(smokeless) has become a breakthrough in solid propellants due to its high performance, but due to the high

cost, composite propellants are accepted. Among the solid base compound propellants, there are three types:

HTPB (hydroxy terminated polybutadiene), APCP and ANCP.

Solid Propellant is primarily used for artillery and rocket propulsion applications. They are high-energy

materials and produce high-temperature gaseous products when burned. The high material density of solid

propellants leads to the high energy density required to produce the required propulsion (the energy produced

per unit mass of propellant is called the energy density). The propellant in the airborne rocket is burned in a

controlled manner to generate the required thrust. Solid propellants are made up of a variety of chemical

components, such as oxidants, fuels, adhesives, plasticizers, curing agents, stabilizers, and cross-linking agents.

The specific chemical composition depends on the combustion characteristics required for the specific task.

Solid propellants are generally classified according to specific applications, such as space launches, missiles,

and weapons. Different chemical components and their ratios lead to different physical and chemical

properties, combustion characteristics and performance.

Components and Properties- Important characteristics of a solid propellant are high specific impulse,

predictable and reproducible burn rate and ignition characteristics, high density, ease of manufacture, low cost

and good aging properties. From a safety point of view, the propellant must produce low noise emissions and

not easily destabilize the combustion process. Propellants are generally classified as homogeneous or

heterogeneous, depending on their chemical composition and physical structure.

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1.1 A solid propellant contains a variety of chemical ingredients as follows –

Table 1.1 HTPB-Based Solid Propellant Formulation

Composite propellants are an important class of solid rocket propellants used in space and missile programs.

They have ammonium perchlorate (AP; 65-70%) as an oxidant, metallic fuels such as aluminum powder (15-

20%) and hydroxy terminated polybutadiene (HTPB) as a prepolymer binder (10-15%) and isocyanate-agents.

based curing agents and processing aids. Today's applications require propellants with excellent mechanical

properties as well as a higher energy content. Due to these conflicting requirements, hydroxy terminated

polybutadiene (HTPB) based propellants are replacing polybutadiene acrylic acrylonitrile (PBAN) and carboxy

terminated polybutadiene (CTPB) based composite propellants, but solid propellant processing It is one of the

key and dangerous operations in Solid Propellant Rocket Engines (SRM).

Since the propellant is viscoelastic, it is very different from the material that the machining is conventionally

carried out. Conventional processing, such as steel, copper is generated heat and is associated with the transfer

of energy to the material to be machined and the tool to which machining is performed. This causes friction

between the tool and the workpiece, the shear of the work parts, as a result, if there is a chip formation and rubbing

of chip on the processing surface. HTPB propellants (hydroxyl finished polybutadiene) used for solid rocket

engines are very sensitive to these factors and machining conditions. The transmission of energy to start

ignition during machining can cause massive fire and risk of explosion.

The main problem associated with creating an initial ignition surface in solid propellant grains is the safe and

efficient processing of the profile/profile. Due to mechanical phenomena, such as heat generated by friction

between the tool and the workpiece, drag of chips on the machined surface, and machining load caused by

impact, the conventional machining of any material is related to the transfer of energy to the material to be cut.

Repeated loading and unloading of tools on propellant materials, etc. However, HTPB-based composite

propellants are sensitive to friction, heat accumulation, electrostatic charge, and impact loads. The energy

associated with these mechanical phenomena, if transferred to the propellant or propellant fragments or

powder, is sufficient to initiate ignition in the propellant shear zone, and then the fire spreads to burn the entire

grain. Because these composite propellants are hygroscopic and produce poor mechanical and ballistic

properties in a humid environment, the application of cutting media outside the cutting area will result in

grains that cannot be classified to meet specific requirements.

Cutters for grinding solid propellant grains are known in the prior art. One of the main disadvantages of these

tools is that they can only be used for specific types of machining operations, such as facing or trimming the

front of a texture, and are not suitable for the contour operations required for machining, such as chamfering,

grooving, trimming, and grooves. Processing etc. , Combined with the coating on the propellant grain. In this

paper we are going to identify and improve the factors which are affecting the surface finish of the material and

then will modify the conical insert so that the surface finish will be enhanced. There are lot of factors in the

machine which affects the surface finish of the material while machining. The three major factors which are






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affecting the surfaces are Speed, Feed and Depth of cut. These factors can also generate vibrations if they are not

used in proportional manner.

1. The approach used in this paper is focusing on the improving terminology of the cutter that is Rake angle,

Relief angle, Force generated while machining surface of material and Speed of rotation of insert to get the

best results. These parameters are used due the software constraints in which the simulation can be done. For

simulation purpose the Ansys Workbench is used due its accuracy and other inputs which are required to run

the simulation is effective over other software.

2. In simulation the results are obtained by putting all the combinations, which would be done by performing

Design of Experiment. Initially the simulation is performed on the conical insert shown in the following

picture, but we then have carried out simulation on the whole set-up which is fitted on the machine to get

more accurate outcomes.

Fig.1.1 Conical Insert

II. PROBLEM DEFINATION

Machining is the process of cutting a piece of raw material into the desired final shape and size through a

controlled material removal process. Machining is part of the manufacture of many metal products, but it can

also be used for materials such as wood, plastics, ceramics, and composites. In our example, the HTPB-based

solid propellant will be machined, but because it is a explosive material, it will produce high temperature

gaseous products when burned. Solid propellants are used primarily in artillery and rocket propulsion

applications. They are very dynamic materials. The high material density of solid propellants leads to the high

energy density required to produce the required propulsion (the energy produced per unit mass of propellant

is called the energy density). The rocket propellant is burned in a controlled manner to generate the required

thrust.

For controlled propellant combustion, the initial ignition surface contours and grooves in the propellant grains

are produced by turn milling operations. The milling process used for this application is a dedicated CNC

turning and milling center, dedicated to solid propellant processing, using a non-sparking hollow profile milling

cutter, four custom HSS tapered blades attached to the tool to cut the effect of propellant pellets. Due to the

explosive nature of the material and hazardous processing operations. The tool is connected to the hollow

chuck, which in turn is connected to the

CDCS (Dust and Debris Collection System). Non-sparking tools are made of non-ferrous materials (non-ferrous

metals), which reduces the risk of sparks when using the tool. Common materials used for non-sparking tools

include brass, bronze, copper-nickel alloy, copper-aluminum alloy, or copper-beryllium alloy. In this case, copper-

titanium is used as the non-sparking material for the tool.

There are some challenges while doing this type of study such as:

HTPB is an explosive material (propellant) and processing conditions can affect processing performance in a

completely

different way than traditional processing.

Since the propellant is highly flammable, the existing mathematical model of the milling process may not be

suitable for this application.






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Due to the chemical reaction between tool material (HSS) and HTPB material, tool wear can accelerate,

resulting in

higher vibration amplitudes.

2.1 Objectives:

To minimize the vibration and surface roughness.

To Design the Insert for Special Purpose Milling Machine/cutter for improving surface finish and

reducing vibration.

2.2 Scope of doing this study:

• By using Design of Experiments we can study and analysis of vibration patterns in milling of HTPB based

solid propellant.

• Identification of factors affecting vibration and surface finish.

• Establish the relationship of the factors with responses.

• Application of multi-objective optimization to get set of Pareto-optimal solutions. Validation and result analysis to

verify its suitability for its practical implementation

Fig. 2.1 Cutter Fig.2.2 Insert

III. METHODOLOGY

Projected Methodology:

Nowadays almost all the industries are using Standard or Conventional machining process. In which all the

process parameters and the machining conditions are set by the day today practices, experimentation and

because of that most of the research work was already done for the conventional machining process and different

cutters and there effect according to the process parameters are also investigated for the particular use also all

the hypothesis is done. But our case is altogether different than conventional process.

In this present case the machining conditions are totally different. Cutters, cutting parameters, machine is also a

special purpose machine, material properties of cutter and the material is to be cut is also different than regular

materials. The workpiece material is used for defense applications and is an explosive material, so the

machining conditions play a very important role in the current working conditions. Because of the discrete

situations and the confidential issues research are limited on this kind of problem. we have proposed a new

methodology for this problem as shown in the flowchart:






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3.1 Identification of Parameters:

Here we have identified some of the parameters which plays significant role while machining the material.

1. Rake angle

The angular relationship between the tooth face or a tangent to the tooth face at a given point and a reference

plane or line. An angular characteristics ground onto the surface of an end mill. The Rake angle is a cutting edge

angle that has large effects on cutting resistance, chip disposal, cutting temperature and tool life.

2. Relief angle

It is the angle between the cutting tool and the workpiece it has just cut. The relief angle on a machine tool is the

angle that the edge of the tool closest to the workpiece makes with the workpiece Side and End Relief Angles:

Relief angles are intended to help eliminate damage to the tool and extend the useful life of the tool. The relief

angle under the cutting edge must be practically large. If the exhaust angle is too large, the cutting tool can be

chip or damaged.

3. Speed

Cutting speed is the speed at the outside edges of the tool as it is cutting. Cutting speed is defined as the speed of

a tool when it is cutting the work. Too fast a cutting speed can cause the tool's edge to break down rapidly, With

too slow a cutting speed, time will be lost for the machining operation, which can result in lost time and low

production rates. The different levels of speeds were selected in such a way that approximately the same cutting

speeds, in feet per minute, were obtained for all different tools.

4. Depth of Cut

The larger the depth of cut, the higher the material removal rate (MRR) that can be achieved, as MRR is

proportional to speed, feed, light and depth of cut. This benefit can be realized by reducing the overall

machining cost.

5. Cutting speed and feed

Cutting speed is the speed difference between the cutting tool and surface of the workpiece it is operating

on. It is expressed in units of distance across the workpiece surface per unit of time, typically meters per minute

(m/min).

There will be optimum cutting speed for each material and set of machining conditions, and the spindle speed

(RPM) can be calculated from this speed. Factors affecting the calculation of cutting speed are:

• The material being machined (steel, brass, tool steel, plastic, wood).

• The material the cutter is made from (High-Carbon Steel, High Speed Steel (HSS), Non Sparking tools).

• The life of the cutter.






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6. Feed

Feed rate is the relative velocity at which the cutter is advanced along the workpiece; its vector is

perpendicular to the vector of cutting speed. Feed rate units depend on the motion of tool and workpiece. Feed

rate is dependent on the:

Type of tool

Required surface finish

Power available at the spindle

Rigidity of the machine and tooling setup.

Strength of the workpiece

Characteristics of the material

Cut Width.

With a milling machine where multi-tipped/multi-fluted cutting tools are used, The feed rate is then

determined by the number of teeth on the cutter as well as the amount of material to be cut per tooth. The

higher the feed rate permissible for a cutting edge to work efficiently, the greater the number of cutting edges. It must

remove enough material to cut rather than rub, and it must also do its fair share of work.

3.1 Selection of Parameters

Here we have selected four parameters that is Rake angle, Relief angle, Force acting on the cutter and Speed of

the cutter which are playing significant role in improving the surface finish and vibration of the cutter. There

are other parameters also, which are significant but as we have to developed the 3D Model the factors which have

selected were playing important role as other factors became redundant. So, for developing 3D model we have used

ANSYS software for performing simulation and vibration analysis. As this are the parameters became the input for

finding the maximum stress and deformation of the cutter.

3.2.1 CAE Analysis:

According to propose methodology, would be using Ansys software for making 3D model to obtain the

maximum stress and deformation, so for that most simulations are performed using the Ansys Workbench

system. Typically while working on the Ansys software the work is break down larger structures into small

components that are each modelled and tested individually. It starts with defining the dimensions of an object,

and then adding weight, pressure, temperature and other physical properties and also the dimensions of the

product. Evidently, the Ansys software simulates and analyses movement, fatigue, fractures, fluid flow,

temperature distribution, electromagnetic efficiency, and other effects over time; as a result of these features,

this software was best suited for the approach.

• For Simulation purpose initially the conical insert would be designed using Catia, and then by introducing

the same model in the Ansys the simulation is carried out.

• According to the combinations, which would be made using Design Of Experiment various Catia models

created, but to get the results in realistic manner, have designed the entire turbine cutter setup with the

insert in the Catia, as shown in the image

Fig. 3.1 Catia Model of Turbine Cutter






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• The main problem was occurred while selecting the material for insert which is Non- Sparking material and

specifically Copper- Titanium material. As there is constraint regarding material properties in Ansys that is

customization of material, therefore have selected Titanium Alloy instead Cu-Ti as it’s having the properties

which are approximately same at some extent as of Cu-Ti.

• All the factors are set according the combination and simulation is performed using nodal vibrations

which results into the maximum principle stress also forces are given at the cutting edge of the insert in order

to obtain the cutter's total deformation

3.2.2 Optimization of Parameters:

Here, we are going to optimize some of the insert parameters which are responsible for the machining of

explosive material. By introducing such parameters we can analyse that which parameters are affecting more to

the surface finish of the material so that The parameters are being optimised in a relatively unobtrusive manner

without affecting other parameters.

3.3 Design of Experiment (DOE):

DOE is a powerful data collection and analysis tool that can be applied to a wide range of experimental scenarios.

It enables the manipulation of multiple input factors in order to determine their effect on a desired output, i.e.

response. DOE can identify important interactions that may be missed when experimenting with one factor at a

time by manipulating multiple inputs at the same time. All possible combinations can be investigated, or only a

subset of the possible combinations can be investigated. It entails creating a series of experiments in which all

relevant factors are systematically varied. When the results of these experiments are analysed, they aid in

identifying optimal conditions, as well as the factors that have the greatest influence.

So, according to DOE we have selected four parameters that is Rake angle, Relief angle, Force acting on the cutter

and Speed of the cutter which are playing significant role in improving the surface finish. There are other

parameters also, which are significant but as we have to find the maximum stress and deformation of the cutter by

3.3.1 DOE Steps:

1. Establish goals.

2. Determine the process variables.

3. Choose an experimental design.

4. Put the design matrix into action.

5. Examine the data to ensure that it is consistent with the experimental assumptions.

6. Analyze and interpret the findings.






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7. Present the results (which may lead to additional runs or DOEs).

3.3.2 Advantage:

reduce time to design or develop new products & processes

improve performance of existing processes

improve reliability and performance of products

achieve product & process robustness

Material evaluation, design alternatives, component and system tolerances, and so on.

3.6 Response surface methodology (RSM):

RSM investigates the connections between a number of explanatory variables and one or more response

variables. The main idea behind RSM is to use a series of carefully designed experiments to arrive at an optimal

response. RSM is the collection of mathematical and statistical techniques that are useful for modelling and

analysing problems in which a response of interest is influenced by several variables and the goal is to optimise

the response.

Typically, response surface methods entail the following steps:

1 The method must move from the current operating conditions to the vicinity of the optimal operating

conditions.

2 In order to maximise the response, the steepest ascent method is used. The same method can be used to

minimise the response, which is known as the steepest descent method.

3 Once the experimenter has located the optimum response, the experimenter must fit a more elaborate

model between the response and the factors.

4 To accomplish this, special experiment designs known as RSM designs are used. The fitted model is used to

determine the optimal operating condition.

IV. RESULTS

4.1 DOE Table:

This is the DOE table that we have created using 5 level 4 factors. The input factors taken are:

1. Rake Angle of tooth

2. Relief Angle of tooth

3. Force applied on cutter

4. No. of grooves on cutter

Table 4.1 Design of Experiment

SR NO Rake

Angle of

tooth

Relief

Angle of

tooth

Force (N) No. of

grooves

Total

deformation

(mm)

Maximum Principal Stress

(MPa)

1 37 21 20 5 0.015513 4.4734

2 37 14 40 5 0.029551 13.985

3 45 10 30 6 0.023757 7.1257

4 45 25 30 6 0.01889 5.9865

5 45 18 50 4 0.043108 12.822

6 37 14 30 8 0.023063 6.2946

The bill of material for the various parts of the assembly are as follows:






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Table 4.2 Bill of Material

Part Quantity Material

Cutter Plate (Bottom and Top) 1 Aluminium Alloy

Inserts 4 Titanium Alloy

Bolts 12 Structural Steel

Arbour 1 Structural Steel

4.1 Material Data

Aluminium Alloy

Aluminium Alloy > Constants

Density 2.77e-006 kg mm^-3

Isotropic Secant Coefficient of Thermal Expansion 2.3e-005 C^-1

Specific Heat Constant Pressure 8.75e+005 mJ kg^-1 C^-1

Aluminium Alloy > Compressive Yield Strength

Compressive Yield Strength MPa

280

Aluminium Alloy > Tensile Yield Strength

Tensile Yield Strength Mpa

280

Aluminium Alloy > Tensile Ultimate Strength

Tensile Ultimate Strength Mpa

310

Aluminum Alloy > Isotropic Elasticity

Temperature C Young’s Modulus Mpa Poisson’s Ratio Bulk Modulus Mpa Shear Modulus Mpa

71000 0.33 69608 26692

Titanium Alloy

Titanium Alloy > Constants




Isotropic Thermal Conductivity 2.19e-002 W mm^-1 C^-1

Isotropic Resistivity 1.7e-003 ohm mm

Titanium Alloy > Compressive Yield Strength


930






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Titanium Alloy > Tensile Yield Strength

Tensile Yield Strength MPa

930

Titanium Alloy > Tensile Ultimate Strength

Tensile Ultimate Strength MPa

1070

Titanium Alloy > Isotropic Elasticity

Temperature C Young's Modulus MPa Poisson's Ratio Bulk Modulus MPa Shear Modulus MPa

96000 0.36 1.1429e+005 35294

Structural Steel

Structural Steel > Constants




Isotropic Thermal Conductivity 6.05e-002 W mm^-1 C^-1

Isotropic Resistivity 1.7e-004 ohm mm

Structural Steel > Compressive Yield Strength


250

Structural Steel > Tensile Yield Strength

Tensile Yield Strength MPa

250

Structural Steel > Tensile Ultimate Strength

Tensile Ultimate Strength MPa

460

Structural Steel > Strain-Life Parameters

Strength

Coefficient MPa

Strength

Exponent

Ductility

Coefficient

Ductility

Exponen t

Cyclic Strength

Coefficient MPa

Cyclic Strain Hardening

Exponent

920 -0.106 0.213 -0.47 1000 0.2

Structural Steel > Isotropic Elasticity

Temperature C Young's Modulus MPa Poisson's Ratio Bulk Modulus MPa Shear Modulus MPa

2.e+005 0.3 1.6667e+005 76923






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CAD Model Mesh Model

Fig 4.1 CAD Model Fig. 4.2 Mesh Model

Nodes: 100110

Elements: 8475

Boundary conditions: 1) Force 20N at insert and 2) Fixed Support at top of Arbour

Fig. 4.3 Boundary conditions

Total deformation:

Max deformation: 0.015513mm at ins

Fig 4.4. Total deformation






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Stress Result:

Maximum stress: 4.3552 MPa

Fig.4.5 Equivalent stress

Principal Stress:

Max principal stress 4.4734 MPa at insert

Fig.4.6 Principle Stress

Project Name: Cutter assembly for Rake Angle: 37 Relief Angle: 14 and No. of grooves: 5 Static and modal

Multiphysics analysis

CAD Model

Fig. 4.7 CAD Model Fig. 4.8 Mesh Model






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Nodes: 101185

Elements: 81452

Boundary conditions: 1) Force 40N at insert and 2) Fixed Support at top

Fig. 4.9 Boundary Conditions

Total deformation: Stress results:

Max deformation: 0.029551mm Maximum stress: 12.864 MPa at insert

Fig 4.10 Total deformation Fig. 4.11 Equivalent stress

Principal Stress:

Max principal stress 13.985 MPa in the insert

Fig.4.12 Principal Stress:






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Project Name: Cutter assembly Rake Angle: 45 Relief Angle: 10 and No. of grooves: 6 Static and modal

Multiphysics analysis.

Cad Model Mesh Model

Fig.4.13 CAD Model Fig. 4.14 Mesh Model

Nodes: 95173

Elements: 53308

Boundary conditions: 1) Force 30N at insert and 2) Fixed Support at top of Arbour

Total deformation: 0.023757mm

Fig.4.15 Boundary conditions Fig.4.16 Total deformation

Stress Results: Principal Stress:

Maximum stress: 5.9865 MPa at insert Max principal stress 7.1257 MPa at insert

Fig.4.17 Equivalent stress Fig.4.18 Principle Stress






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Project Name: Cutter assembly Rake Angle: 45 Relief Angle: 25 and No. of grooves: 6 Static and modal

Multiphysics analysis.

Cad Model Mesh Model

Fig.4.19 CAD Model Fig. 4.20 Mesh Model

Nodes: 92676

Elements: 60267

Boundary conditions: 1) Force 30N at insert and 2) Fixed Support at top of Arbor.

Fig.4.21 Boundary conditions






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Total deformation: Stress Results:

Max deformation: 0.01889mm Maximum stress: 5.9865 MPa at insert

Fig.4.22 Total deformation Fig.4.23 Equivalent stress

Principal Stress:

Max principal stress 5.4234 MPa at insert

Fig.4.24 Principal Stress:

For the rest of the assembly mentioned in the DOE table as well as the assemblies mentioned above, these are the

values for the Total Deformation, Maximum stress and Maximum Principal Stress.

Table 4.3 Results

Sr.No Rake angle of

tooth

Relief angle of

tooth

Force (N) No Of

grooves

Total Deformation

(mm)

Maximum

stress (MPa)

Maximum Principal

stress (MPa)

1 37 21 20 5 0.015513 4.3552 4.4734

2 37 14 40 5 0.029551 12.864 13.985

3 45 10 30 6 0.023757 5.2791 7.1257

4 45 25 30 6 0.01889 5.9865 5.9865

5 45 18 50 4 0.043108 9.5248 12.822

6 37 14 30 8 0.023063 4.6254 6.2946






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Fig.4.25 Variation in result of deformation for different assembly conditions

Fig.4.26 Variation in result of Maximum Principal stress for different assembly condition

Optimization:

We have optimized the output parameters using Simple additive weight method.

Table 4.4 Optimization

Simple Additive Weight Method

1 1 2 (Max)

0.524957 0.319871 0.844828145

0.652986 0.627784 1.280770425

0.821228 0.747248 1.568476138

0.359864 0.348885 0.708748328

0.672636 0.710673 1.383308464

V. CONCLUSION 1. It is revealed from the study that, Copper Titanium is the best suitable materialfor Conical Insert out of

Copper Beryllium and Copper Alloy due to its complete safety, excellent hardness and durability.

2. It is observed from gathered data that the major factors which affects the surface finish most, are Rake

Angle, Relief Angle And Force acting on the insert while machining and No. of Grooves on the insert.

3. The best suitable combination obtained from the study for the Conical Insert is Rake Angle with 37◦, Relief Angle

with 21◦, and the Force of 20N and with No. Of Grooves 5 on the conical insert.

4. For Optimal Combination, the minimum values obtained for Maximum Principle Stress and the Minimum

Deformation for the Conical Insert are 4.4734MPa and 0.015513mm

NO. OF OBSERVATIONS

TOTA

L D

EFO

RM

AT

ION






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[2] Shalini Chaturvedi et.al“REVIEW: Solid Propellants:AP/HTPB Composite Propellants” Arabian Journal of

Chemistry.

[3] Rohit K. Mahallea et.al “Study for Analysis of Effect Of Machining Parameter & To Predict The Behavior of

Propellant Grain During Machining Operation” 2nd International Conference On Structural Integrity And

Exhibition 2018.

[4] Andrzej Weremczuka et.al “The Concept of Active Elimination of Vibrations In Milling Process” 15th CIRP

Conference On Modelling Of Machining Operations.

[5] M.S. Patil et.al “Ballistic and Mechanical Properties of HTPB Based Composite Propellants” Journal of

Hazardous Materials, 19 (1988) 2’71-278 Elsevier Science Publishers B.V., Amsterdam - Printed in The

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[6] R. Venkata Rao et.al “Parameter optimization of a multi-pass milling process using non-traditional

optimization algorithms” Applied Soft Computing.

[7] K. Kishore et.al “Development of a Hollow contouring cutter for machining of Solid Rocket motor

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[8] Mark A. Lewis “End Milling of Elastomers— Fixture Design and Tool Effectiveness for Material

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